What is the difference between `fs.unlink()` and `fs.unlinkSync()` in Node.js?

Q: What is the difference between `fs.unlink()` and `fs.unlinkSync()` in Node.js?

`fs.unlink()` is an asynchronous method for deleting files. It takes a callback function to handle the result. `fs.unlinkSync()` is a synchronous method for deleting files. It blocks the execution until the file is deleted.

Difficulty: 2/10

fs.unlink, asynchronous vs synchronous, error handling

1
fs.unlink() is an asynchronous method for deleting files. It takes a callback function to handle the result.
2
fs.unlinkSync() is a synchronous method for deleting files. It blocks the execution until the file is deleted.

Scenario Questions

0-2 years experience

1You need to delete a temporary file after processing it in a small script. How would you use fs.unlink() versus fs.unlinkSync() and why would you pick one?
2If you call fs.unlinkSync() inside a try/catch block and the file doesn't exist, what does Node do and how would you handle that situation?

2-5 years experience

1Your API endpoint receives a file upload and after storing it you must delete the original temporary file. Walk me through how you'd implement the deletion, including error handling and response timing.

Follow-up Questions

What happens to the request latency if you accidentally use the sync version inside an HTTP handler?
How does the Node.js event loop behave when a synchronous file operation blocks?
Can you describe a way to test that your error handling works for both async and sync deletions?